Black Rock Prison by Fernando Trujillo Sanz

What is the worst sentence that can befall a convict in Illinois? Not life in prison, not lethal injection. The worst punishment is to be sent to Black Rock Prison, a black-walled fortress whose exact location no one knows. The new warden of this unusual prison controls every dimension of each and every one of the convicts unfortunate enough to be sent there.

The inmates soon will discover that they are not normal people, nor have they been imprisoned there by chance. The sentences awaiting them will be carried out in the shadow of a sinister threat. It isn’t long before they find out that much more than their own lives is riding on solving the mystery of Black Rock.